Chapter 2.5, Problem 46E

Horizontal asymptotes Determine $\underset{x\to \infty }{\lim }f\left(x\right)$ and $\underset{x\to -\infty }{\lim }f\left(x\right)$ for the following functions Then give the horizontal asymptotes of f (if any).

46.     $f\left(x\right)=\frac{\sqrt{x^2+1}}{2x+1}$